Electrical reproducer



ELECTRI CAL REPRODUCER Filed Aug. 28, 1926 gum/whoa Patented Aug. 13,1929..

UNITED STATES PATENT OFFICE.

ELECTRICAL REPRODUCER.

Application filed August as, 1926. Serial No. 132,096.

This invention relates to electrical reproducers for phonographs, andhas for its object theproduction of'an efficient sound reproducingmechanism, wherein the magnetic flux in the pole pieces variesconstantly with variations of the armature and follower or needle.

Another object of my invention includes the production of a constructionwhich is simple in construction and reliable and effective in operation.

A Other objects will appear hereinafter, and I attain these objects bythe construction illustrated in the accompanying drawings, in

which Fig. 1 is a plan view of a construction which embodies theprinciples of my inven- 'tion.

Fig. 2 is a plan view with the cover removed.

Fig. 3 is a sectional view taken on the line 33 of Fig. 1.

Fig. 4 is a view taken on the line 4- 1 of Fig. 2, and

Fig. 5 is a view of the armature and pole pieces.

The same numerals refer to like parts throughout the several views.

In a preferred form of construction, to which, however, I do not desireto be understood as limiting myself otherwise than as stated in theappended claims, I provide two permanent magnets 10 and 11. Thesemagnets are preferably semi-circular in shape and are placed with theirlikepoles opposite pole pieces 12 and "13. These pole pieces are securedto the shell or casing 14, by any suitable means as screws 15 and 16.For convenience, pole piece 12' may be re garded as the north pole andpole piece 13 as the south pole. The north pole is longer than thesouthpole, and it carries the magnetic coil 17 afiixed thereon at rightangles to the axial line of the pole. The respective ends 19 and 20 ofthe coil wire are secured to the lead wires 21 and 22 by binding pieces23 and 24:. These pieces are carried on disk 25 of insulating material.

The south pole carries the armature 26, which is pivotally saddled onthe pole by the pivot saddle 27, so as to swing back and forth inresponse to the motion of the record needle 28, as it follows thegrooves in the record (not shown). The action of the armature causes thedistance between the armature tail 2 9 and the north pole to vary, andconsequently the magnetic flux therein and in coil 17 varies also. Anysuitable means as spring 30, normally holds the tail 29 and the northpole spaced in proper relation. A 6 cap 31 protects the construction,and a thumb screw 82 holds the needle secure. The magnetic properties ofthe magnet pieces must be permanent, and I use for this purpose cobaltsteel as best suited for my purose.

While I have shown and described a specific construction, Ido notthereby desire to be understood as having thus limited myselfunnecessarily.

What I claim, therefore, as new and useful, and desire to secure byLetters Patent is:

1. An electric reproducer, comprising a pair of permanent magnets, polepieces arranged between said magnets, a coil carried by one of said polepieces, and a saddle piece pivotally mounted on the other of said polepieces, said saddle piece carrying a needle and having a tail pieceextending to the other of said pole pieces.

2. An electric reproducer comprising a pair of permanent magnets, polepieces arranged between said magnets, a coil carried by one of said polepieces, and a saddle piece pivotally mounted on the other of said polepieces, said saddle pieces'carrying a needle and .having 'atail pieceextending to the other of said pole pieces, and means for controllingthe position of said saddle piece. I

-3. An electric reproducer comprising two permanent semi-circularmagnets, a case for holding sald' magnets with their like poles oppositeeach ather, a pole piece between the north pole of the magnets and apole piece between the south pole of said magnets, a coil carried bysaidnorth pole and a saddle piece carried by said south pole.

4. An electric reproducer comprising two permanent semi-circularmagnets, a case for holding said magnets with their like poles oppositeeach other, a pole piece between the north pole of the magnets and apole piece between the south pole of said magnets, a coil carried bysaid north pole and a'saddle piece carried by said south pole, saidsaddle piece having a needle for following the grooves in a phonographrecord and a tail piece extending over a portion of the north 1O pole,and means for controlling the position of the saddle piece.

In testimony whereof I have hereunto set my hand on this 23rd day ofAugust, A. 1).,

IGOR S. BOBROVSKY.

